This invention relates to railroad grade crossings, and in particular to railroad grade crossings incorporating precast concrete panels with elastomeric seals between the panels and the rails.
When a railroad track crosses a roadway it is necessary to bring the space between the roadway and the rails, and the space between the rails, up to grade. This is accomplished by installing grade crossing elements into these spaces. In busy city streets it has become common to use precast concrete panels for this purpose. Concrete panels wear well and, therefore, with-stand the heavy traffic occurring on busy city streets. In addition, precast concrete panels are quickly installed which reduces the time the street is unavailable during installation of the crossing. Finally, precast concrete panels are easily and quickly removed to access the track for repairs and maintenance.
When precast concrete crossing panels are used it is desirable to place elastomeric seals between the panels and the rails. These seals provide a positive flangeway which prevents water from getting beneath the panels and weakening the ballast. The seals also create a cushioning transition between the rails and the concrete panels, which makes for a smoother ride for vehicles crossing the tracks and prevents chipping of the corners of the panels. The seals also reduce the transmission of vibration from the rails to the panels. Finally, elastomeric seals electrically isolate the rails from the panels. Precast concrete grade crossing panels with elastomeric seals are shown, for example, in Davis, U.S. Pat. No. 5,181,657 and Martin, U.S. Pat. No. 4,899,933.
With both of these prior art crossing systems the seal and concrete panels are separate elements. In Davis, the seal is partially overlaid by the panel, and the panel holds the seal in place. In Martin, the seal is inserted between the panel and the rail after the panel is installed. In either case, the seal complicates installation of the grade crossing, and with Martin the seal can become dislodged in use.
The subject invention overcomes this problem with the prior art precast concrete panel/elastomeric seal grade crossing systems by casting the seals into the panels to form integral panel seal units. In a preferred embodiment of the invention, the seal has a ledge with an downwardly projecting lip that is imbedded in the concrete panel.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.